BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns cosmetic compositions containing malonic acid salts which combat the signs of skin aging.
2. The Related Art
A soft, supple and flexible skin has a marked cosmetic appeal and is an attribute of normal functioning epidermis. As human skin ages with advancing years, the epidermis can become folded, ridged or furrowed to form wrinkles. These signal loss of youthful appearance and herald the transition to old age. Exposure to excessive doses of sunlight accelerates the transition process. Also, the outer layer of the epidermis known as the stratum corneum can become dry and flaky following exposure to cold weather or excessive contact with detergents or solvents. Loss of skin moisture thereby results and the skin begins to lose the soft, supple and flexible characteristics.
Emollients such as fats, phospholipids and sterols have in the past been used to soften wrinkled or dry skin. These emollients are only partially effective as a remedy for skin in poor condition.
The use of hydroxy carboxylic acids for enhancing the quality of human skin has been known for some time. There is no doubt that alpha-hydroxy carboxylic acids are effective much beyond the common emollients.
U.S. Pat. No. 4,424,234 (Alderson et al.) discloses skin treatment compositions incorporating alpha-hydroxycaproic acid and alpha-hydroxycaprylic acid or mixtures thereof in compositions that have a pH value of less than 7, usually from 2 to 4. Yu and Van Scott have patented widely in this area. For instance, U.S. Pat. No. 4,105,782 reports amines or ammonium salts of alpha-hydroxy carboxylic acids in the treatment of acne or dandruff. In U.S. Pat. No. 4,105,783 and U.S. Pat. No. 4,197,316, these compounds are suggested for the treatment of dry skin. U.S. Pat. No. 4,234,599 discloses the use of alpha-hydroxy carboxylic acids, their esters or amine salts in the treatment of keratoses. More recently, U.S. Pat. No. 5,091,171 focused attention on these compounds as being effective against age spots, wrinkles and aging related skin changes.
While hydroxy carboxylic acids hold much therapeutic promise, the materials have been found to irritate human skin on repeated topical applications. The irritation may range from a sensation of tingling, itching and burning to clinical signs of redness and peeling. Causes for such irritation have been linked to the lowering of pH in the stratum corneum of human skin. Low pH has been suggested as provoking disturbances in intercorneocyte bondings resulting in adverse skin reactions, specialty in some individuals with sensitive skin.
Organic acids other than alpha-hydroxy functionatized have been disclosed in the cosmetic literature. For instance, U.S. Pat. No. 5,641,495 (Jokura et at.) discloses in combination a ceramide or pseudoceramide, a dicarboxylic acid and a salt of a dicarboxylic acid. The Examples illustrate sodium and potassium salts of succinic acid. Lower molecular weight dicarboxytic acids such as malonic may also be utilized. Although excellent moisturization and little accompanying irritation occurs, there is no suggestion that this system combats signs of aging such as advent of fine lines and wrinkles. Improvements in the general anti-aging technology of skin remains as an unfulfilled need of the consumer.
Accordingly, it is an advantage of the present invention to provide new cosmetic ingredients in compositions which are effective at controlling and even eliminating the signs of aging, particularly fine lines, wrinkles, sagging skin, poor tone and age spots.
SUMMARY OF THE INVENTION
A cosmetic composition is provided which includes:
(i) from about 0.0001 to about 30% by weight of a mono-hydroxy substituted amine salt of matonic acid; and
(ii) from about 1 to about 99.9% by weight of a cosmetically acceptable carrier.
Furthermore, the present invention provides a set of new cosmetically active ingredients. In particular, the dimethylaminoethanol salts of malonic acid have proven very effective.
DETAILED DESCRIPTION OF THE INVENTION
We have now found a class of salts which are at least as effective as alpha-hydroxy carboxylic acids. These salts are based on a select dicarboxylic acid neutralized with a select class of amines to form the active salt ingredient. These salts may either be partially or fully neutralized carboxylic salts as represented by general formulas (I) and (II):
+[X] 2[O2CCH2CO2]−2 II
wherein X is a protonated salt of a mono-hydroxy substituted amine, the amine in non-protonated form having general formula III:
wherein R1 and R2 are branched or unbranched C1-C30 radicals selected from the group consisting of alkyl, cycloalkyl, alkenyl, aryl, alkylaryl, alkoxyalkyl and combinations thereof;
R3 is a branched or unbranched C1-C30 radical selected from the group consisting of alkylene, cycloalkylene, arylene and combinations thereof; and
R1 with R2 can optionally form a ring and independently R1 with R3 can form a ring.
Illustrative mono-hydroxy amines include dimethylaminoethanol, diethyl aminoethanol, diisopropylaminoethanol, ethylmethylamino-ethanolamine, methylbutylaminoethanolamine, dimethylamino-methanol, diethylaminomethanol, methylethylaminomethanol, dimethylaminopropyanol, diethylaminopropanol, dipropylamino-propanol, ethylpropylaminopropanol, diphenylaminoethanol, methyl-phenylaminoethanol, para-toluoylmethylaminoethanol, dimethylaminophenylethanol, piperidinylethanol, 2-methylpyridinyl-ethanol, 2-pyrrolidonylethanol and pyrrolylethanol. Most preferred is dimethylaminoethanol (DMAE).
Amounts of the amine neutralized malonate salt may range from about 0.0001 to about 30%, preferably from about 0.1 to about 15%, more preferably from about 0.5 to about 10%, optimally from about 1 to about 8% by weight of the cosmetic composition.
The present invention can utilize as the active ingredient salt I, salt II or mixtures of these salts. When mixtures are present the molar ratio of mono-salt I to di-salt II may range from about 1000:1 to about 1:1000, preferably from about 10:1 to about 1:500, more preferably from about 2:1 to about 1:200, optimally from about 1:1 to about 1:20.
Compositions of this invention may have a pH ranging from about 2.5 to about 8.5, preferably from about 3 to about 8, optimally from about 4 to less than about 7.
Compositions of this invention will also include a cosmetically acceptable carrier. Amounts of the carrier may range from 1 to 99.9%, preferably from about 70 to about 95%, optimally from about 80 to about 90%. Among the useful carriers are water, emollients, fatty acids, fatty alcohols, humectants, thickeners and combinations thereof. The carrier may be aqueous, anhydrous or an emulsion. Preferably the compositions are aqueous, especially water and oil emulsions of the W/O or OW variety. Water when present may be in amounts ranging from about 5 to about 95%, preferably from about 20 to about 70%, optimally from about 35 to about 60% by weight.
Emollient materials may serve as cosmetically acceptable carriers. These may be in the form of silicone oils, synthetic esters and hydrocarbons. Amounts of the emollients may range anywhere from about 0.1 to about 95%, preferably between about 1 and about 50% by weight.
Silicone oils may be divided into the volatile and nonvolatile variety.
The term “volatile” as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic (cyclomethicone) or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms.
Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially nonvolatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5×10−6 to 0.1 m2/s at 25° C. Among the preferred nonvolatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 1×10−5 to about 4×10−4 m2/s at 25° C.
Another class of nonvolatile silicones are emulsifying and non-emulsifying silicone elastomers. Representative of this category is Dimethicone/Vinyl Dimethicone Crosspolymer available as Dow Corning 9040, General Electric SFE 839, and Shin-Etsu KSG-18. Silicone waxes such as Silwax WS-L (Dimethicone Copolyol Laurate) may also be useful.
Among the ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl mono-stearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters. Particularly useful are pentaerythritol, trimethylolpropane and neopentyl glycol esters of C1-C30 alcohols.
(4) Wax esters such as beeswax, spermaceti wax and tribehenin wax.
(5) Sterols esters, of which cholesterol fatty acid esters are examples thereof.
(6) Sugar ester of fatty acids such as sucrose polybehenate and sucrose polycottonseedate.
Hydrocarbons which are suitable cosmetically acceptable carriers include petrolatum, mineral oil, C11-C13 isoparaffins, polyalphaolefins, and especially isohexadecane, available commercially as Permethyl 101A from Presperse Inc.
Fatty acids having from 10 to 30 carbon atoms may also be suitable as cosmetically acceptable carriers. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erucic acids.
Fatty alcohols having from 10 to 30 carbon atoms are another useful category of cosmetically acceptable carrier. Illustrative of this category are stearyl alcohol, lauryl alcohol, myristyl alcohol and cetyl alcohol.
Humectants of the polyhydric alcohol-type can be employed as cosmetically acceptable carriers. Typical polyhydric alcohols include glycerol, polyalkylene glycols and more preferably alkylene polyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, isoprene glycol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. The amount of humectant may range anywhere from 0.5 to 50%, preferably between 1 and 15% by weight of the composition.
Thickeners can be utilized as part of the cosmetically acceptable carrier of compositions according to the present invention. Typical thickeners include crosslinked acrylates (e.g. Carbopol 982®), hydrophobically-modified acrylates (e.g. Carbopol 1382®), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, hydroxypropyl methocellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenam, pectin and combinations of these gums. Inorganics may also be utilized as thickeners, particularly clays such as bentonites and hectorites, fumed silicas, and silicates such as magnesium aluminum silicate (Veegum®). Amounts of the thickener may range from 0.0001 to 10%, usually from 0.001 to 1%, optimally from 0.01 to 0.5% by weight.
Cosmetic compositions of the present invention may be in any form. These forms may include lotions, creams, roll-on formulations, sticks, mousses, aerosol and non-aerosol sprays and pad-applied formulations.
Surfactants may also be present in cosmetic compositions of the present invention. Total concentration of the surfactant when present may range from about 0.1 to about 40%, preferably from about 1 to about 20%, optimally from about 1 to about 5% by weight of the composition. The surfactant may be selected from the group consisting of anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a C10-C20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C2-C10 alkyl phenols condensed with from 2 to 20 moles of alkylene oxide;
mono- and di-fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di-C8-C20 fatty acids; and polyoxyethylene sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g. methyl gluconamides) are also suitable nonionic surfactants.
Preferred anionic surfactants include soap, alkyl ether sulfates and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, C8-C20 acyl isethionate, C8-C20 alkyl ether phosphates, C8-C20 sarcosinates and combinations thereof.
Sunscreen actives may also be included in compositions of the present invention. Particularly preferred are such materials as ethylhexyl p-methoxycinnamate, available as Parsol MCX®, Avobenzene, available as Parsol 1789® and benzophenone-3, also known as Oxybenzone. Inorganic sunscreen actives may be employed such as microfine titanium dioxide, zinc oxide, polyethylene and various other polymers. Amounts of the sunscreen agents when present may generally range from 0.1 to 30%, preferably from 2 to 20%, optimally from 4 to 10% by weight.
Preservatives can desirably be incorporated into the cosmetic compositions of this invention to protect against the growth of potentially harmful microorganisms. Suitable traditional preservatives for compositions of this invention are alkyl esters of para-hydroxybenzoic acid. Other preservatives which have more recently come into use include hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Cosmetic chemists are familiar with appropriate preservatives and routinely choose them to satisfy the preservative challenge test and to provide product stability. Particularly preferred preservatives are phenoxyethanol, methyl paraben, propyl paraben, imidazolidinyl urea, sodium dehydroacetate and benzyl alcohol. The preservatives should be selected having regard for the use of the composition and possible incompatibilities between the preservatives and other ingredients in the emulsion. Preservatives are preferably employed in amounts ranging from 0.01% to 2% by weight of the composition.
Compositions of the present invention may also contain vitamins. Illustrative water-soluble vitamins are Niacinamide, Vitamin B2, Vitamin B6, Vitamin C and Biotin. Among the useful water-insoluble vitamins are Vitamin A (retinol), Vitamin A Palmitate, Ascorbyl Tetraisopalmitate, Vitamin E (tocopherol), Vitamin E Acetate and DL-panthenol. Total amount of vitamins when present in compositions according to the present invention may range from 0.001 to 10%, preferably from 0.01% to 1%, optimally from 0.1 to 0.5% by weight.
Another adjunct ingredient can be that of an enzyme. Particularly preferred is superoxide dismutase, commercially available as Biocell SOD from the Brooks Company, USA.
Skin lightening agents may be included in the compositions of the invention. Illustrative substances are placental extract, lactic acid, niacinamide, arbutin, kojic acid, resorcinol and derivatives including 4-substituted resorcinols and combinations thereof. Amounts of these agents may range from about 0.1 to about 10%, preferably from about 0.5 to about 2% by weight of the compositions.
Desquamation agents are further optional components. Illustrative are the alpha-hydroxycarboxylic acids and beta-hydroxycarboxylic acids. Among the former are salts of glycolic acid, lactic acid and malic acid. Salicylic acid is representative of the beta-hydroxycarboxylic acids. Amounts of these materials when present may range from about 0.1 to about 15% by weight of the composition.
A variety of herbal extracts may optionally be included in compositions of this invention. Illustrative are green tea, chamomile, licorice and extract combinations thereof. The extracts may either be water soluble or water-insoluble carried in a solvent which respectively is hydrophilic or hydrophobic. Water and ethanol are the preferred extract solvents.
Anti-microbiat agents may also be included in the compositions of this invention. Illustrative are trichlosan, trichlocarban, Octopyrox® and zinc pyrithione. Amounts may range from about 0.01 to about 5%, preferably from about 0.1 to about 0.5% by weight of the composition.
Colorants, fragrances, opacifiers and abrasives may also be included in compositions of the present invention. Each of these substances may range from about 0.05 to about 5%, preferably between 0.1 and 3% by weight.
The term “comprising” is meant not to be limiting to any subsequently stated elements but rather to encompass non-specified elements of major or minor functional importance. In other words the listed steps, elements or options need not be exhaustive. Whenever the words “including” or “having” are used, these terms are meant to be equivalent to “comprising” as defined above.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material ought to be understood as modified by the word “about”.
The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise illustrated.